Face to face retail sales transactions take place at the point of sale or what is commonly referred to as the checkout line or counter. It is at this location that the customer pays for the goods purchased, typically by either cash, check, charge or debit card. To effectuate the sale, many retailers presently use electronic devices to facilitate and provide a record of transactions. Such a point of sale system may include a scanner for reading coded product information, a terminal for manual entry of transaction information and storage of currency, a display for displaying transaction information and a printer which may be used to produce a documentary record or journal for the business and a printed receipt for the customer.
As part of the check out procedure, the sales price of each item purchased is typically entered into the point of sale terminal. Each item price and a total is printed by the point of sale printer on a customer receipt and may also be printed on a separate journal by the same point of sale printer. A tax due is commonly also determined and printed on the customer receipt. The customer receipt is then provided from the printer to the customer.
In a two station point of sale printer, the second printer station maintains a journal record of all sales transactions. This provides a written record for auditing sales activity such as gross sales amounts and taxes collected during a journal period covered by the journal record. This information could be used, for example, by a taxing authority to determine if a retailer has submitted payment to the taxing authority of all taxes collected from customers.
Where governmental authorities acquire an interest in retail journal information, such as through value added tax laws or sales tax laws, the respective tax laws frequently define the format and content of printed receipts and mandate secure methods of sales data capture. It is known to respond to such "fiscal" requirements by providing a fiscal printer such as the 3F printer from International Business Machines, Inc. of Armonk, N.Y. With such a fiscal printer, a secure (i.e., tamper-evident or resistant enclosure) logic card with dedicated nonvolatile random access memory (NVRAM) and electronically programmable read only memory (EPROM) may be placed both physically and logically between a point of sale terminal and a point of sale printer which generates customer receipts and journal records.
With a fiscal printer, such as the Model 3F, the point of sale terminal may be connected to a fiscal base device which is secured to the point of sale printer and which controls all printing functions by a communications link such as a serial communications link. An example of such a fiscal base is illustrated in FIG. 1.
Point of sale terminal 10 is connected to fiscal base 24 over communications link 22. Fiscal printer 20 in turn includes both fiscal base 24 and two station printer 26.
Fiscal base 24 includes a fiscal processor 28 or other control means for controlling journal and printing operations. Fiscal base 24 further includes a battery backed (nonvolatile) random access memory 30 to store intermediate sales and tax totals during a journal period. As shown in FIG. 1, fiscal base 24 further includes a separate program EPROM 32 and fiscal memory EPROM 34. A separate fiscal memory EPROM 34 is provided, encased in epoxy, for permanent storage of data, which typically includes daily sales and tax totals for some number of daily journal periods depending upon the capacity of fiscal memory EPROM 34. Program EPROM 32 may then be used for program information or data values used by fiscal processor 28. Also shown in FIG. 1 is a time of day clock 36 which may be used for tracking transactions and journal periods.
Two station printer 26 is controlled by fiscal processor 28. A first printing station provides a customer receipt station whose printing is controlled by fiscal processor 28 to assure that the sales receipt provided to the customer has the correct data on it related to a particular transaction. The second station provides a journal station which records transaction by transaction sales data and daily reports. The paper journals from the journal station of printer 26 are, typically, subsequently stored for tax audit purposes pursuant to the fiscal laws of various taxing authorities.
Various countries with fiscal taxing laws have expressed an interest in replacing the current system of journal paper tape storage with a digital electronic journal record. Such a transition could reduce equipment, consumable, record-handling and storage costs for retailers. It could allow the use of single station lower cost printers and halve paper consumption. While both retailers and fiscal authorities may recognize the potential advantages of an electronic journal, there are continued concerns that such electronic journal files could be readily modified by an end user intent on defrauding the government.
One proposed solution also relying on a fiscal printer device approach but using an electronic journal has been proposed. This approach utilizes a checksum calculated from all of the data stored in the fiscal secured memory using a key that is not known outside the fiscal printer. The entire journal data block may then be transferred from the fiscal base 24 to a point of sale terminal 10 rather than being maintained in the secure fiscal printer. However, this approach fails to address all of the objectives for such a verifiable electronic journal system. For example, to validate the data in the point of sale terminal, the data must be fed back to the fiscal base where an associated checksum can be obtained from fiscal memory and compared to a new checksum generated from the data downloaded from the point of sale terminal. Furthermore, depending upon the size of the journal unit transferred to and from the point of sale terminal, a large volume of nonvolatile random access memory may be required in the fiscal base. In addition, it may be necessary to sustain data in fiscal memory EPROM for a greater period of time for potential verification requiring an increased size of fiscal memory EPROM. Finally, this approach is limited in that it does not readily allow for remote verification of journal records.